Electric meter



` Patented Apr. 25, |899. T'. DUNCAN. LEcTmc METER. (Applieation led May23, 189B.)

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No. 623,525. Patent-empf. 25, |899.

. T. DUNCAN. Y

ELEJTHI()v METER.

(Applicatiun mod May 28, 1898.) (No Model.) 2 Sheets-Sheet 2.

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@Wwe/Kom MM www QM 2 QMW AfrnNr prima@ THOMAS DUNCAN, OF FORT NTAYNE,INDIANA.

ELECTRIC METER.

SPECIFICATION forming part of Letters :Patent No. 623,525, dated April25, 1899.

Application filed May 23, 1898. Serial No. 681,403.

T0 all whom t may concern:

Be it known that I, THOMAS DUNCAN, a citizen of the United States,residing at Fort Vayne, in the county of Allen and State of Indiana,have invented certain new and useful Improvements in Electric Meters, ofwhich the following is a specification.

lWly invention relates to improvements in alternating-currentinduction-motor meters in which a closed revoluble metallic diskarmature is operated by the influence of a shifting magnetic fieldproduced by the resultant magnetic effect of two or more magnetic fieldsdiffering in phase from each other and operating in mutual cooperation.

One of the objects of the present invention is to reduce the cost ofmanufacture of meters of this class by making them simple and of veryfew parts.

Another object of the invention is to-so arrange the-actuating-coilsthat they will all be upon the same side of the armature, therebyreducing to a minimum the cost of assembling or putting together andrendering the cleaning and repairing easily accomplished by any ordinarycentral-station employee.

A third object is to enable a change in the speed to be made Whenchecking or adjusting without having to alter or change any of the coilsor windings or Vary the retardation.

In carrying out the foregoing objects I employ the following'elements inmy improvement: a source of alternating electric currents, supply-mains,a series field-coil through which passes the current supplying thetranslating devices, a shunt eld-coil Wound with smaller wire andreceiving its currents from the terminals of the said series field-coilor from the said supply-mains, an iron core provided with a plurality ofprojecting polepieces, some of which support the said series and shuntfield-coils and become magnetic cores for them, a revoluble aluminiumdisk armature mounted upon a suitable spindle and operated by theinductive iniiuence of the said series and shunt ield-coils, anadjustable iron part or keeper arranged adjacent to the upper andopposite face of the disk armature from the series and shunt fieldcoilsand also from the iron core upon which said series and shunt coils aremounted, means for producing the necessary retardation in- (No model.)

cident to all forms of motor-meters, which consists in employing awinged fan if the torque varies as the square of the current in amperesthrough the meter or the usual form of magneto-electric drag if thetorque of the meter varies directly or proportional to the energyconsumed, and a suitable registering mechanism.

It has been the practice in the construction of motor-meters of thistype to operate the disk armature by arranging the energizing coil orcoils of one phase adjacent to its upper face or surface and theenergizing Vcoil or coils of a different phase adjacent to its lowerface, and the resultant magnetic action of these two sets of coilsproduced rotation of the intervening disk. In the present improvementthe actuatingcoils of different phase are located adjacent to one sideof the disk, and the resultant field produced by these energizing-coilsis caused to act inductively upon the disk armature and set it inrotation. For the purpose of regulating and adjusting the torque andspeed of the disk I employ an iron keeper suitably arranged adjacent tothe opposite surface of the disk armature from which theenergizing-coils are located. rlhe function of this keeper is to assistin attracting or drawing the magnetism of the energizing-coils throughthe disk armature, thereby adding to the efficiency of operation of themeter.

In the accompanying drawings, which form part of this specification,Figure l is an elevation showing the energizing-coils in section. Fig. 2is also an elevation showing the energizing-coils in section and thespeed-regulating core l5 adjustable. Fig. 3 differs from Fig. 2 in beingwired up or connected to measure the watts. Fig. 4L shows a modifiedform of core carrying the energizing-coils with speed-regulating corehorizontally adjustable. Fig. 5 shows still another modification of thecore which supports the energizingcoils and arranged as a Coulomb-meter.Fig.

6 is similar to Fig. 5 with the exception of its being connected toregister the watts.

The operation of the arrangement shown in Fig. l is as follows: When animpulse of current from the transformer 2 passes through the seriesiield-coil 6, it magnetizes the polar projection or limb of the ironcore 7, upon IOO which the said coil is mounted. If the translatingdevices are non-inductive, the current traversing the coil 6 will beapproximately in phase with the pressure or electromotive force of themains 3 and 4, with the exception, possibly, of whatever lag isintroduced into this circuit by the reaction of the core 7, but which inthe present instance may be altogether omitted. Another coil S, woundwith finer wire and having a greater number of turns than the seriesfield-coil G and herein referred to as the shunt field-coil, is mountedupon the other projecting pole-piece of the iron core 7. The terminals 9and 10 of this shunt iieldcoil S are connected in parallel to or shuntedaround the terminals of the said series fieldcoil, and since the coil Shas a greater number of turns than the coil G the current passingthrough the former will lag perceptibly behind that passing through thelatter or coil G. This difference in time period between the currents inthe two coils is accompanied by a corresponding difference of phasebetween the magnetisms of the two coils. These two magnetic fields,however, combine into a resultant shifting magnetic field in a mannernow well understood by those skilled in the art and which sets the diskarmature 14 in rotation. The disk armature is mounted upon a spindle 22,which also carries a worm 17 and which meshes with and operates asuitable registering mechanism 16. To make the rate of speedproportional to the current through the coil G, I have secured upon thecircumference of the disk armature a number of aluminium vanes 13. Foradjusting the speed of the armature I use the iron portion or keeper 15,placed adjacent to the upper surface of said armature, and by raising orlowering it more or less of the lines of force of the shifting iield arecaused to eut the disk or armature. I can also employ the resistance 11for adjusting the speed. Said resistance may also be used to adjust orvary the phase of the current through the coils 8 in a well-understoodmanner. In supporting the iron core 7 suitable screws 12, as shown, maybe used.

Fig. 2 is also a front elevation of the present improvement, showing thefield-coil 6 and 3 in section. A secondary coil 20 is also shown woundupon the same core with the coil 8 and having a resistance 21 connectedin series with it. rlhe function of this coil 2O is to retard or lag themagnetism of the polar projection upon which the said coils S and 2O aremounted. The iron keeper 15 in this Iigure shows a slot 19 and set-screw18 for adjusting its position or distance from the surface of the disk.

Fig. 3 differs from Fig. 2 in that it shows the terminals 9 and 10 ofthe shunt field-coil connected to the main leads 3 and 4 instead of theterminals of the series Held-coil, and also by the addition of theimpedance-coil 24 in series with the shunt-coil S. This arrangement ofthe connections permits of the instrument measuring the energy or wattsinstead of the current in amperes only, as in the case of Figs. 1 and 2.A change in the retardating is also necessary with these counections,and to secure the proper relation between torque and speed I have shownthe usual permanent magnets 23 embracing the disk armature 14. Theimpedance-coil 24 and resistance 2l are for adjusting the magnetism ofthe coils S and 2O to quadrature with the electromotive force of themains 3 and 4.

In Figs. 1, 2, and 3 I have described my improvement in its simplestform and that in which only two projecting pole-pieces on the core 7 areshown. I prefer, however, to employ more than two, as is shown in Figs.3, 4, and 5. By so doing I obtain greater accuracy and eliminate to aperceptible degree any trace of mutual induction between the twofield-coils 6 and 8. In Fig. 4 the core 7 has a third polar projection25 midway the coils 6 and 8 and the projecting pole-pieces supportingthem. This becomes a leakage-path for the magnetism of both coils 0 andS. Fig. 5 shows a core 7 having four polar extensions, of which the twoend or outer ones support the field-coils and the two inner areleakage-poles 25 and 25. Said figure also shows a resistance 2G inseries with the coil 8, the purpose of which is to vary the lag or phaseof the current, also the strength of said current in the coil S. Fig. 6is similar to Fig. 5 as regards the core 7, but the connections of thefield-coils are arranged to measure the watts, as in Fig. 3. Theydiffer, however, from Fig. 3 in that the secondary coil 2O of Fig. 3 isomitted and a resistance 11 is connected across the terminals of thecoil 8, as shown. By suitably proportioning the resistance 11 thecurrent through the coil 8 is retarded until it is in quadrature with orninety degrees behind the circuit-leads 3 and 4, which enables the meterto measure with accuracy inductive loads.

I do not wish to be understood as limiting myself to the exact number ofpoles shown 011 the core 7, as other modifications might readily suggestthemselves to those skilled in the art-such, for instance, as theaddition of two more poles-t'. e. by putting one at each end of the core7-and which would bound the coils G and S upon their outer sides.

Having described myinvention, what I desire to secure by Letters Patentis- 1. The combination in an induction-motor meter of a revolublemetallic disk armature, a laminated iron core 7 having a plurality ofpoles adjacent to one side of said armature, a laminated iron core 15adjacent to the opposite side of said armature and having its adjacentsurface parallel to the surface of said disk armature in its revolution,coils for magnetizing the said iron core 7, and a suitable means forretarding the revolutions of said armature.

2. The combination in an induction-motor meter of a revoluble metallicdisk armature,

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an adjustable iron core 15 having a portion of its surface adjacent toand parallel with the said disk armature, an iron core 7 adjacent to theopposite side of said disk armature, coils for magnetizing the said core7, and means for retarding the revolutions of said disk armature.

3. The combination in an induction-motor meter of a revoluble metallicdisk armature, retarding-fans attached to and revoluble with said diskarmature, an unwound iron core 15 adjacent to the upper surface of saiddisk armature, means for Varying the distance between the adjacentsurfaces of the said iron core 15 and the said disk armature,an ironcore 7 adjacent to the lower surface of said disk armature, coils formagnetizing said iron core 7, and a suitable registering mechanism.

4. The combination in an induction-motor meter of a revoluble aluminiumdisk armature, means for retarding the revolutions of said armature, anunwound iron core 15 having its lower surface parallel with and adjafcent to the upper surface of said armature, means for Varying thedistance between the adjacent surfaces of the said iron core 15 and thesaid disk armature as set forth, au iron core 7 adjacent to the lowersurface of the said disk armature, coils for magnetizing the said ironcore 7, a spindle 22, and a suitable registering mechanism.

In testimony that I claim the foregoing as my invention I have signed myname, in the presence of two witnesses, this 20th daj1 of May, 1898.

fr'HoMAs DUNoAN.

Witnesses:

EDWARD A. BARNES, M. GRACE WEBBER.

